Multi-Component Telepresence System and Method

ABSTRACT

The present invention provides systems and methods for performing robotically-assisted surgical procedures on a patient. In particular, a three-component surgical system is provided that includes a non-sterile drive and control component, a sterilizable end effector or surgical tool and an intermediate connector component that includes mechanical elements for coupling the surgical tool with the drive and control component and for transferring motion and electrical signals therebetween. The drive and control component is shielded from the sterile surgical site, the surgical tool is sterilizable and disposable and the intermediate connector is sterilizable and reusable. In this manner, the intermediate connector can be sterilized after a surgical procedure without damaging the motors or electrical connections within the drive and control component of the robotic system.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/034,854 filed on Feb. 21, 2008; which is a division of U.S. patentapplication Ser. No. 10/922,346 filed on Aug. 19, 2004, now U.S. Pat.No. 7,357,774; which is a continuation of U.S. patent application Ser.No. 10/004,399 filed on Oct. 30, 2001, which is a continuation of U.S.patent application Ser. No. 09/406,360 filed on Sep. 28, 1999, now U.S.Pat. No. 6,346,072; which is a continuation of U.S. patent applicationSer. No. 08/975,617 filed on Nov. 21, 1997, now U.S. Pat. No. 6,132,368;and which claims the benefit under 35 USC 119(e) of U.S. ProvisionalPatent Application No. 60/033,321 filed on Dec. 12, 1996, the fulldisclosures of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

This invention relates to robotically-assisted surgical manipulators andmore particularly to systems and methods for performing teleroboticsurgical procedures on a patient while providing the surgeon with thesensation of physical presence at the surgical site.

In robotically-assisted or telerobotic surgery, the surgeon typicallyoperates a master controller to remotely control the motion of surgicalinstruments at the surgical site from a location that may be remote fromthe patient (e.g., across the operating room, in a different room or acompletely different building from the patient). The master controllerusually includes one or more hand input devices, such as joysticks,exoskeletal gloves or the like, which are coupled to the surgicalinstruments with servo motors for articulating the instruments at thesurgical site. The servo motors are typically part of anelectromechanical device or surgical manipulator (“the slave”) thatsupports and controls the surgical instruments that have been introduceddirectly into an open surgical site or through trocar sleeves into abody cavity, such as the patient's abdomen. During the operation, thesurgical manipulator provides mechanical articulation and control of avariety of surgical instruments, such as tissue graspers, needledrivers, electrosurgical cautery probes, etc., that each perform variousfunctions for the surgeon, e.g., holding or driving a needle, grasping ablood vessel, or dissecting, cauterizing or coagulating tissue.

This new method of performing telerobotic surgery through remotemanipulation has, of course, created many new challenges. One suchchallenge results from the fact that a portion of the electromechanicalsurgical manipulator will be in direct contact with the surgicalinstruments, and will also be positioned adjacent the operation site.Accordingly, the surgical manipulator may become contaminated duringsurgery and is typically disposed of or sterilized between operations.Of course, from a cost perspective, it would be preferable to sterilizethe device. However, the servo motors, sensors, encoders and electricalconnections that are necessary to robotically control the motorstypically cannot be sterilized using conventional methods, e.g., steam,heat and pressure or chemicals, because they would be damaged ordestroyed in the sterilization process.

Yet another challenge with telerobotic surgery systems is that a surgeonwill typically employ a large number of different surgical instrumentsduring a procedure. Since the number of instrument holders are limiteddue to space constraints and cost, many of these surgical instrumentswill be attached and detached from the same instrument holder a numberof times during an operation. In laparoscopic procedures, for example,the number of entry ports into the patient's abdomen is generallylimited during the operation because of space constraints as well as adesire to avoid unnecessary incisions in the patient. Thus, a number ofdifferent surgical instruments will typically be introduced through thesame trocar sleeve during the operation. Likewise, in open surgery,there is typically not enough room around the surgical site to positionmore than one or two surgical manipulators, and so the surgeon'sassistant will be compelled to frequently remove instruments from theholder and exchange them with other surgical tools.

What is needed, therefore, are improved telerobotic systems and methodsfor remotely controlling surgical instruments at a surgical site on apatient. These systems and methods should be configured for easysterilization so that they can be reused after the components have beencontaminated during an operation. In addition, these systems and methodsshould be designed to minimize instrument exchange time during thesurgical procedure.

SUMMARY OF THE INVENTION

The present invention provides systems and methods for performingremote, robotically-assisted surgical procedures on a patient whileproviding the surgeon with the sensation of physical presence at thesurgical site (i.e., telepresence). In particular, a three-componentsurgical system is provided that includes a non-sterile drive andcontrol component, a sterilizable end effector or surgical tool and anintermediate connector component that includes mechanical elements forcoupling the surgical tool with the drive and control component, and fortransferring motion from the drive component to the surgical tool. Thedrive and control component is shielded from the sterile surgical site,the surgical tool is sterilizable and disposable and the intermediateconnector is sterilizable and reusable. In this manner, the intermediateconnector can be sterilized after a surgical procedure without damagingthe motors or electrical connections within the drive and controlcomponent of the robotic system.

The drive and control component of the present invention generallyincludes the drive actuators, e.g., motors, gears or pulleys, etc., andpositioning devices that are necessary to articulate the surgical toolat the surgical site. In addition, the drive and control component willusually include the encoders and electrical connectors required tocouple the component to a servomechanism to form a master/slavetelerobotic surgical system. In a specific configuration of theinvention, this component comprises a manipulator assembly having adrive assembly and a multiple degree of freedom manipulator arm. The armand drive assembly are covered by a sterile drape to effectively shieldthese components from the sterile surgical field during the operation.In this way, the portion of the system including motors, encoders andfragile electronics does not have to be sterilized because it isseparated from the sterile field surrounding the surgical site.

The intermediate connector includes a sterile adaptor that extendsthrough an opening in the sterile drape to couple the sterile surgicaltool with the manipulator arm. The adaptor includes a plurality ofmotion and electrical feed-throughs for articulating the surgical tool,and for sending electrical signals to and from the tool, e.g., force andtorque feedback signals, etc. In one configuration, the intermediatecomponent includes a scope adaptor for coupling a viewing scope, such asan endoscope coupled to a camera mount and a camera, to the manipulatorarm. In another configuration, the intermediate connector includes asurgical instrument assembly coupled to the sterile adaptor. Thesurgical instrument assembly will usually include a surgical tool, whichmay comprise a variety of articulated tools with end effectors, such asjaws, scissors, graspers, needle holders, micro dissectors, stapleappliers, tackers, suction irrigation tools, clip appliers, ornon-articulated tools, such as cutting blades, cautery probes,irrigators, catheters or suction orifices.

In a preferred configuration, the surgical instrument assembly willfurther include a wrist unit for removably coupling the surgical tool tothe adaptor on the manipulator assembly. The wrist unit comprises anelongate shaft with a distal wrist coupled to the surgical tool forproviding articulation of the tool about the distal wrist. During asurgical procedure, the telerobotic system will usually include avariety of surgical instrument assemblies, each having a wrist unit witha different surgical tool attached. The wrist units can be quickly andeasily coupled and decoupled from the manipulator assemblies tofacilitate instrument exchange during the procedure. In an exemplaryembodiment, the wrist unit is reposable, and it includes a mechanism forcounting the number of times the wrist unit is used to inhibit furtheruse of the unit.

The manipulator assembly provides a plurality of degrees of freedom tothe wrist unit and surgical tool including pitch and yaw movement of thetool about the wrist, rotation about the wrist shaft axis, axialmovement and articulation of the end effector on the surgical tool. Inaddition, the manipulator assembly preferably provides pitch and yawmotion of the wrist unit and the surgical tool about axes perpendicularto the wrist shaft. The motors of the drive assembly are locatedproximally from the arm and the intermediate component, whichfacilitates cleaning, decreases the cost of manufacturing the assemblyand decreases the inertia of the surgical tool and wrist unit. In apreferred configuration, the manipulator assembly will include a remotecenter positioning device, such as a parallelogram linkage, forconstraining motion of the wrist unit and/or surgical tool about adesired fixed center of rotation. This fixed center of rotation may belocated on the wrist unit shaft, at the distal wrist, or in endoscopicprocedures, coincident with the entry incision within the patient'sbody.

In an exemplary embodiment, the three-component surgical manipulator ofthe present invention is part of a telerobotic system in which thesurgeon manipulates input control devices and views the operation via adisplayed image from a location remote from the patient. The systemincludes a servomechanism coupled to one or more manipulator assembliesto control the wrist units and surgical tools in response to thesurgeon's manipulation of the input control devices. Position, force,and tactile feedback sensors (not shown) may also be employed totransmit position, force, and tactile sensations from the surgical toolsback to the surgeon's hands as he/she operates the telerobotic system. Amonitor is coupled to the viewing scope such that the displayed image ofthe surgical site is provided adjacent the surgeon's hands. The image ispreferably oriented so that the surgeon feels that he or she is actuallylooking directly at the operating site. This configuration provides thesurgeon with telepresence, or the perception that the input controldevices are integral with the surgical tools.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an operating room, illustrating atelerobotic surgical system and method according to the presentinvention.

FIG. 2 is an enlarged view of the operating room of FIG. 1 illustratinga pair of mounting joints coupled to an operating table according to thepresent invention.

FIG. 3A is a perspective view of a robotic surgical manipulatoraccording to the present invention that is partially covered by asterile drape.

FIG. 3B is a perspective view of the robotic surgical manipulatorwithout the sterile drape to illustrate a multiple degree of freedom armcoupling a driving assembly with a wrist unit and a surgical tool.

FIG. 4 illustrates the robotic surgical manipulator of FIGS. 3A-3Bincorporating a camera and endoscope for viewing the surgical site.

FIG. 5 is a partial view of the robotic manipulator of FIGS. 3A-3B,illustrating mechanical and electrical couplings between the arm and thewrist unit.

FIG. 6 is a partially cut-away sectional view of a forearm and acarriage of the manipulator of FIGS. 3 a and 3B.

FIG. 7 is a perspective view of the wrist unit according to the presentinvention.

FIG. 8 is a side cross-sectional view of a portion of the roboticmanipulator, illustrating the arm and the drive assembly.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS

The present invention provides a multi-component system and method forperforming robotically-assisted surgical procedures on a patient,particularly including open surgical procedures, neurosurgicalprocedures, such as stereotaxy, and endoscopic procedures, such aslaparoscopy, arthroscopy, thoracoscopy and the like. The system andmethod of the present invention is particularly useful as part of atelerobotic surgical system that allows the surgeon to manipulate thesurgical instruments through a servomechanism from a remote locationfrom the patient. To that end, the manipulator apparatus or slave of thepresent invention will usually be driven by a cinematically-equivalentmaster to form a telepresence system with force reflection. Adescription of a suitable slave-master system can be found in co-pendingpatent application Ser. No. 08/517,053, filed Aug. 21, 1995 (AttorneyDocket No. 287-004810), the complete disclosure of which is incorporatedherein by reference.

Referring to the drawings in detail, wherein like numerals indicate likeelements, a telerobotic surgical system 2 is illustrated according tothe present invention. As shown in FIG. 1, telerobotic system 2generally includes one or more surgical manipulator assemblies 4 mountedto or near an operating table O, and a control assembly 6 for allowingthe surgeon S to view the surgical site and to control the manipulatorassemblies 4. The system 2 will also include one or more viewing scopeassemblies 19 and a plurality of surgical instrument assemblies 20adapted for being removably coupled to manipulator assemblies 4(discussed in detail below). Telerobotic system 2 usually includes atleast two manipulator assemblies 4 and preferably three manipulatorassemblies 4. Of course, the exact number of manipulator assemblies 4will depend on the surgical procedure and the space constraints withinthe operating room among other factors. As discussed in detail below,one of the assemblies 4 will typically operate a viewing scope assembly19 (in endoscopic procedures) for viewing the surgical site, while theother manipulator assemblies 4 operate surgical instruments 20 forperforming various procedures on the patient P.

Control assembly 6 may be located at a surgeon's console C which isusually located in the same room as operating table O so that thesurgeon may speak to his/her assistant(s) A and directly monitor theoperating procedure. However, it will be understood that the surgeon Scan be located in a different room or a completely different buildingfrom the patient P. Control assembly 6 generally includes a support 8, amonitor 10 for displaying an image of the surgical site to the surgeonS, and one or more controller(s) 12 for controlling manipulatorassemblies 4. Controller(s) 12 may include a variety of input devices,such as joysticks, gloves, trigger-guns, hand-operated controllers,voice recognition devices or the like. Preferably, controller(s) 12 willbe provided with the same degrees of freedom as the associated surgicalinstrument assemblies 20 to provide the surgeon with telepresence, orthe perception that the controller(s) 12 are integral with theinstruments 20 so that the surgeon has a strong sense of directlycontrolling instruments 20. Position, force, and tactile feedbacksensors (not shown) may also be employed on instrument assemblies 20 totransmit position, force, and tactile sensations from the surgicalinstrument back to the surgeon's hands as he/she operates thetelerobotic system. One suitable system and method for providingtelepresence to the operator is described in co-pending patentapplication Ser. No. 08/517,053, filed Aug. 21, 1995, (Attorney DocketNo. 0287S-004810), which has previously been incorporated herein byreference.

Monitor 10 will be suitably coupled to the viewing scope assembly 19such that an image of the surgical site is provided adjacent thesurgeon's hands on surgeon console 6. Preferably, monitor 10 willdisplay an inverted image on a display 18 that is oriented so that thesurgeon feels that he or she is actually looking directly down onto theoperating site. To that end, an image of the surgical instruments 20appears to be located substantially where the operator's hands arelocated even though the observation points (i.e., the endoscope orviewing camera) may not be from the point of view of the image. Inaddition, the real-time image is preferably transformed into aperspective image such that the operator can manipulate the end effectorand the hand control as if viewing the workspace in substantially truepresence. By true presence, it is meant that the presentation of animage is a true perspective image simulating the viewpoint of anoperator that is physically manipulating the surgical instruments 20.Thus, a controller (not shown) transforms the coordinates of thesurgical instruments 20 to a perceived position so that the perspectiveimage is the image that one would see if the camera or endo scope waslocated directly behind the surgical instruments 20. A suitablecoordinate transformation system for providing this virtual image isdescribed in patent application Ser. No. 08/239,086, filed May 5, 1994,(Attorney Docket No. 0287S-003300), the complete disclosure of which isincorporated herein by reference.

As shown in FIG. 1, a servomechanism 16 is provided for transferring themechanical motion of controllers 12 to manipulator assemblies 4.Servomechanism 16 may be separate from, or integral with manipulatorassemblies 4. Servomechanism 16 will usually provide force and torquefeedback from the surgical instruments 20 to the hand-operatedcontrollers 12. In addition, servomechanism 16 will include a safetymonitoring controller (not shown) that may freeze or at least inhibitall robot motion in response to recognized conditions (e.g., exertion ofexcessive force on the patient, “running away” of the manipulatorassemblies 4, etc.). The servomechanism preferably has a servo bandwidthwith a 3 dB cut off frequency of at least 10 Hz so that the system canquickly and accurately respond to the rapid hand motions used by thesurgeon. To operate effectively with this system, manipulator assemblies4 have a relatively low inertia and the drive motors 170 (see FIG. 8)have relatively low ratio gear or pulley couplings. Any suitableconventional or specialized servomechanism may be used in the practiceof the present invention, with those incorporating force and torquefeedback being particularly preferred for telepresence operation of thesystem.

Referring to FIG. 7, surgical instrument assemblies 20 each include awrist unit 22 and a surgical tool 24 removably attached to wrist unit22. As discussed in detail below, each wrist unit 22 generally includesan elongate shaft 56 having a proximal cap 58 and a distal wrist 60pivotally coupled to surgical tool 24. Each wrist unit 22 issubstantially the same, and will have different or the same surgicaltools 24 attached thereto, depending on the requirements of the surgicalprocedure. Alternatively, wrist units 22 may have specialized wrists 60designed for individual surgical tools 24 so that the wrist units 22 maybe used with conventional tools 24. As shown in FIG. 1, the instrumentassemblies 20 are usually assembled onto a table T or other suitablesupport adjacent the operating table O. According to a method of thepresent invention (described below), wrist units 22 and their associatedsurgical tools 24 can be quickly exchanged during the surgical procedureby coupling and decoupling wrist unit shafts 56 from manipulatorassemblies 4.

Referring to FIG. 2, each manipulator assembly 4 is preferably mountedto operating table O by a mounting joint 30. Mounting joints 30 providea number of degrees of freedom (preferably at least 5) to assemblies 4,and they include a brake (not shown) so that assemblies 4 can be fixedat a suitable position and orientation relative to the patient. Joints30 are mounted to a receptacle 32 for mounting joints 30 to operatingtable O, and for connecting each manipulator assembly 4 toservomechanism 16. In addition, receptacle 32 may connect joints 30 toother systems, such as an RF electrical power source, asuction-irrigation system, etc. Receptacle 32 includes a mounting arm 34that is slidably disposed along an outer rail 36 of operating table O.Of course, manipulator assemblies 4 may be positioned over the operatingtable O with other mechanisms. For example, the system may incorporate asupport system (coupled to the ceiling or a wall of the operating room)that moves and holds one or more manipulator assemblies 4 over thepatient.

Referring now to FIGS. 3-8, manipulator assembly 4 will be described infurther detail. Manipulator assembly 4 is a three-component apparatusthat includes a non-sterile drive and control component, a sterilizableend effector or surgical tool (i.e., surgical instrument assembly 20)and an intermediate connector component. The intermediate connectorincludes mechanical elements for coupling the surgical tool 24 with thedrive and control component, and for transferring motion from the drivecomponent to the surgical tool 24. As shown in FIG. 3B, the drive andcontrol component generally includes a drive assembly 40 and a multipledegree of freedom robotic arm 42 coupled to a mounting bracket 44, whichis adapted for mounting onto mounting joints 30 (FIG. 2). Preferably,drive assembly 40 and robotic arm 42 are pivotally coupled to bracket 44about an X-axis, which extends through a remote center of sphericalrotation 45 (see FIG. 8, discussed in further detail below). Manipulatorassembly 4 further includes a forearm assembly 46 fixed to a distal end48 of arm 42, and a wrist unit adaptor 52 coupled to forearm assembly 46for mounting wrist unit 22 and surgical tool 24 to manipulator assembly4.

For endoscopic procedures, manipulator assembly 4 additionally includesa cannula adaptor 64 attached to a lower portion of forearm 46 formounting a cannula 66 to manipulator assembly 4. Alternatively, cannula66 may be an integral cannula (not shown) that is built into forearmassembly 46 (i.e., non-removable). Cannula 66 may include a forcesensing element (not shown), such as a strain gauge or force-sensingresistor, mounted to an annular bearing within cannula 66. The forcesensing bearing supports surgical tool 24 during surgery, allowing thetool to rotate and move axially through the central bore of the bearing.In addition, the bearing transmits lateral forces exerted by thesurgical tool 24 to the force sensing element, which is connected toservomechanism 16 for transmitting these forces to controller(s) 12. Inthis manner, forces acting on surgical tools 24 can be detected withoutdisturbances from forces acting on cannula 66, such as the tissuesurrounding the surgical incision, or by gravity and inertial forcesacting on manipulator assembly 4. This facilitates the use ofmanipulator assembly in a robotic system because the surgeon willdirectly sense the forces acting against the surgical tool 24.

As shown in FIG. 3A, manipulator assembly 4 further includes a steriledrape 70 sized to cover substantially the entire manipulator assembly 4.Drape 70 has a pair of holes 72, 74 sized and arranged so that wristunit adaptor 52 and cannula adaptor 64 may extend through holes 72, 74to mount wrist unit 22 and cannula 66 to manipulator assembly 4. Steriledrape 70 comprises a material configured to effectively shieldmanipulator assembly 4 from the surgical site so that most of thecomponents of assembly 4 (i.e., arm 42, drive assembly 40 and forearmassembly 46) do not have to be sterilized prior to, or following thesurgical procedure.

As shown in FIG. 3A, wrist unit adaptor 52 and cannula adaptor 64 extendthrough holes 72, 74 of drape 70 so that forearm assembly 46 and theremainder of manipulator assembly 4 remain shielded from the patientduring the procedure. Wrist unit adaptor 52 and cannula adaptor 64 arepreferably manufactured as reusable components that will be sterilizedbecause these components extend into the sterile field of the surgicalsite. Wrist unit and cannula adapters 52, 64 may be sterilized by normalmethods, i.e., steam, heat and pressure, chemicals and the like.Referring again to FIG. 3B, wrist unit adaptor 52 includes an opening 80for receiving shaft 56 of wrist unit 22. As discussed in detail below,shaft 56 can be laterally urged through opening 80 and snap-fit intoadaptor 52 such that the non-exposed portion of wrist unit adaptor 52remains sterile (i.e., remains on the sterile side of drape 70 oppositethe sterile field). Wrist unit adaptor 52 may also include a latch (notshown) for securing wrist unit 22 therein. Similarly, cannula adaptor 64includes an opening 82 for snap fitting cannula 66 thereto such that thenon-exposed portion of adaptor 64 remains sterile during the surgicalprocedure.

As shown in FIG. 4, wrist unit adaptor 52 may also be configured toreceive a viewing scope 100 for viewing the surgical site. Forendoscopic procedures, viewing scope 100 can be a conventionalendoscope, which typically includes a rigid, elongated tube 102containing a lens system (not shown) and a camera mount 104 at theproximal end of the tube 102. A small video camera 106 is preferablyattached to the camera mount 104 and connected to video monitor 10 toprovide a video image of the procedure. Preferably, the scope 100 has adistal end (not shown) configured to allow lateral or angled viewingrelative to tube 102. The viewing scope may also have a guidable tipthat can be deflected or rotated by manipulating an actuator on aproximal end of tube 102. This type of scope is commercially availablefrom Baxter Healthcare Corp. of Deerfield, Ill., or Origin Medsystems,Inc. of Menlo Park, Calif.

As shown in FIG. 4, viewing scope 100 further includes a scope adaptor110 for coupling viewing scope 100 to wrist unit adaptor 52. Scopeadaptor 110 is sterilizable, ETO and autoclavable, and it includes aplurality of motion feed-throughs (not shown) for transferring motionfrom drive assembly 40 to scope 100. In the preferred configuration, themotion includes pitch and yaw motion, rotation about the Z-axis, andmovement along the Z-axis.

Referring now to FIGS. 5 and 6, forearm assembly 46 will be described infurther detail. As shown in FIG. 5, forearm assembly 46 includes ahousing 120 fixed to arm 42 and a movable carriage 122 slidably coupledto housing 120. Carriage 122 slidably mounts wrist unit adaptor 52 tohousing 120 for moving wrist unit adaptor 52 and wrist unit 20 in theZ-direction. In addition, carriage 122 defines a number of openings 123for transferring motion and electrical signals from forearm assembly 46to wrist unit adaptor 52. As shown in FIG. 6, a plurality of rotatableshafts 124 are mounted within housing 120 for transferring motion fromarm 42 through openings 123 to wrist unit adaptor 52 and wrist unit 22.Rotating shafts 124 preferably provide at least four degrees of freedomto wrist unit 22, including yaw and pitch motion of surgical tool 62about wrist 60 of wrist unit 22, rotation of wrist unit 22 about theZ-axis and actuation of tool 62. Of course, the system may be configuredto provide more or less degrees of freedom, if desired. Actuation oftool 62 may include a variety of motions, such as opening and closingjaws, graspers or scissors, applying clips or staples and the like.Motion of wrist unit 22 and tool 62 in the Z direction is provided by apair of carriage cable drives 126 extending between rotatable pulleys128, 129 on either end of forearm housing 120. Cable drives 126 functionto move carriage 122 and wrist unit 22 in the Z direction relative toforearm housing 120.

As shown in FIG. 6, distal end 48 of arm 42 includes a coupling assembly130 having a plurality of motion feed-throughs 132 for transferringmotion from arm 42 to forearm assembly 46. In addition, couplingassembly 130 includes a number of electrical connectors (not shown) fortransferring electrical signals from arm 42 to wrist unit 22. Similarly,wrist unit adaptor 52 includes a plurality of motion feed-throughs (notshown) and electrical connections (not shown) for transferring motion,and for sending and receiving electrical signals to and from wrist unit22 (e.g., for sending and receiving force and torque feedback signalsfrom the surgical site to controllers 12). The components on either sideof coupling assembly 130 and wrist unit adaptor 52 have a finite rangeof motion. Usually, this range of motion will be at least 1 revolutionand preferably greater than 1 revolution. These ranges of motion arealigned with each other when the forearm assembly 46 is mechanicallycoupled to the coupling assembly 130 and when wrist unit adaptor 52 ismechanically coupled to the forearm 46.

Referring to FIG. 7, wrist unit 22 will now be described in furtherdetail. As shown, wrist unit 22 includes a hollow shaft 56 having a cap58 attached to its proximal end and a wrist 60 attached to its distalend. Wrist 60 includes a coupling (not shown) for removably coupling avariety of surgical tools 62 to shaft 56. Shaft 56 is rotatably coupledto cap 58 for providing rotation of shaft 56 and tool 62 about thelongitudinal axis of shaft 56 (i.e., the Z axis). Cap 58 houses amechanism (not shown) for transferring motion from wrist unit adaptor 52to drive cables (not shown) within shaft 56. The drive cables aresuitably coupled to drive pulleys within shaft 56 to pivot tool 62 aboutwrist 60, and to actuate end effectors 140 on tool 62. Wrist 60 may alsobe operated by other mechanisms, such as differential gears, push-rods,or the like.

Tool 62 is removably coupled to wrist 60 of wrist unit 22. Tool 62 willpreferably include an end effector having a tactile sensor array (notshown) for providing tactile feedback to the surgeon. Tool 62 mayinclude a variety of articulated tools, such as jaws, scissors,graspers, needle holders, micro dissectors, staple appliers, tackers,suction irrigation tools, clip appliers, that have end effectors drivenby wire links, eccentric cams, push-rods or other mechanisms. Inaddition, tool 62 may comprise a non-articulated instrument, such ascutting blades, probes, irrigators, catheters or suction orifices.Alternatively, tool 62 may comprise an electrosurgical probe forablating, resecting, cutting or coagulating tissue. In the latterembodiment, wrist unit 22 will include a conductive element, such as aproximal banana plug coupled to a lead wire or rod extending throughshaft 56 to tool 62.

Referring to FIGS. 4 and 8, a specific configuration of the drive andcontrol component of the present invention (i.e., the robotic arm 42 anddrive assembly 40) will be described in further detail. As discussedabove, arm 42 and drive assembly 40 are rotatably coupled about a pairof pins 150 extending from mounting bracket 44. Arm 42 preferablycomprises an elongate, substantially rigid body 152 with a distal end 48coupled to forearm assembly 48 and a proximal end 154 pivotally coupledto drive assembly 40 and bracket 44 for rotation about pitch and yaw orthe X and Y axes (note that the Y axis is perpendicular to the page andextends through point 45, see FIG. 8). Of course, arm 40 may have otherconfigurations, such as an elbow arm (similar to the human arm),prismatic arm (straight extendable) or the like. A stationary yaw motor156 is mounted to mounting bracket 44 for rotating arm 42 and driveassembly 40 about the X-axis. Drive assembly 40 also includes a pitchmotor 158 coupled to arm 42 for rotating arm about the Y axis. A pair ofsubstantially rigid linkage elements 160, 162 extend from bracket 44 torobotic arm 42 to pivotally couple arm 42 to bracket 44 about Y-axis.One of the linkage elements 160 is pivotally coupled to arm 42, and theother linkage element 162 is pivotally coupled to a third linkageelement 164 extending parallel to arm 42. Preferably, robotic arm 42 isa channel shaped rigid element that at least partially houses the thirdlinkage element 164. The linkage elements 160, 162 and 164 and arm 42form a parallelogram linkage in which the members are connected togetherin a parallelogram for relative movement only in the plane formed by themembers.

The Z-axis of wrist unit 22 held at the distal end 48 of arm 42intersects the x axis of the parallelogram linkage described above.Wrist unit 22 has a remote center of spherical rotation about theposition indicated by the numeral 45 in FIG. 8. Thus, the distal end ofwrist unit 22 can be rotated about its own axis or the X and Y axeswhile the remote center of rotation 45 remains at the same location. Amore complete description of a remote center positioning device can befound in co-pending application Ser. No. 08/504,301, filed Jul. 20, 1995(Attorney Work Docket 287-002940), now U.S. Pat. No. 5,931,882, thecomplete disclosure of which is incorporated herein by reference. Itshould be noted that arm 42 and drive assembly 40 may be used with abroad range of positioning devices other than that described above andshown in FIG. 8, such as a stereotaxic positioner, a fixed gimbal or thelike.

Referring again to FIG. 8, drive assembly 40 further includes aplurality of drive motors 170 coupled to arm 42 for rotation therewith.Pitch and yaw motors 156, 158 control the motion of arm 42 (and drivemotors 170) about the X and Y axes and drive motors 170 control themotion of wrist unit 22 and surgical tool 24. Preferably, at least fivedrive motors 170 are coupled to arm 42 for providing at least fivedegrees of freedom to wrist unit 24. Drive motors 170 will preferablyinclude encoders (not shown) for responding to servomechanism 16 andforce sensors (not shown) for transmitting force and torque feedback tothe surgeon S. As discussed above, the five degrees of freedompreferably include movement of carriage 122 and wrist unit 22 in theZ-direction, rotation of wrist unit 22 about the Z-axis, pitch and yawrotation of surgical tool 62 around wrist 60 and actuation of tool 62.

As shown, cables 172 extend from each motor 170 around a motor drivepulley 174, an idler pulley 176 within arm 42 and along a relativelylarge pot capstan 178 to minimize the effect of friction torque oncables 172. The cables 172 each extend around another idler pulley 180at distal end 48 of arm 42, around a coupling drive pulley 182 and backto the motor 170. The cables 172 will preferably be tensioned at themotor drive pulley 174 and anchored there as well as at the couplingdrive pulley 182. As shown in FIG. 8, coupling drive pulley 182 isconnected to a plurality of smaller pulleys 184 within coupling assembly130 via a plurality of cables 186 for transferring motion from themotors 170 to wrist unit adaptor 52.

A method for performing a surgical procedure on a patient according tothe present invention will now be described with reference to FIGS. 1-9.As shown in FIG. 2, mounting joints 30 are attached to receptacle 32,which is attached to the operating table O by sliding mounting arm 34along rail 36. Each manipulator assembly 4 is then attached to itsrespective mounting joint 30 and articulated into the proper positionand orientation relative to the patient P. Receptacles 32 are thencoupled to servomechanism 16 and other systems that may be requiredduring the surgical procedure, such as an RF power supply, asuction/irrigation system, etc. Sterile drapes 70 are placed over themanipulator assemblies 4 before, during or after the patient has beenanesthetized (FIG. 3A). To prepare for the surgical procedure,manipulator assemblies 4 may or may not be chemically cleaned prior tocovering them with drapes 70. Wrist unit adapters 52, cannula adapters64 and scope adapters 110 are snapped onto forearm assemblies 46 ofmanipulator assemblies 4 (see FIGS. 3B and 5). The number and relativepositions of scope adapters 110 and wrist unit adapters 52 will, ofcourse, depend on the individual surgical procedure (e.g., cannulaadapters 64 may not be required for open surgical procedures).

During the surgical procedure, surgical instrument assemblies 20 arecoupled to their respective manipulator assemblies 4 by laterally urgingeach respective wrist unit shaft 56 through opening 80 of wrist unitadaptor 52. Each wrist unit 22 will have suitable identification means(not shown) to quickly and easily indicate what type of tool 24 isconnected to the wrist unit 22. When the surgeon wishes to changesurgical tools 24, he or she manipulates controller(s) 12 so thatcarriage 122 moves to a top or proximal position of travel along forearmassembly 46 (see FIG. 3B). In this position, surgical tool 24 is withincannula 66 or during open procedures, removed from the surgical site.The assistant(s) A then pulls upward on wrist cap 58 to release thelatch (not shown), thereby allowing wrist unit 22 to slide furtherupwards and out of cannula 66. The assistant(s) A may then pull wristunit 22 laterally to decouple it from wrist unit adaptor 52. When wristunit 22 is no longer coupled to adaptor 52, the control mechanismunderstands that the system in is “tool change mode”, and drivescarriage 122 to the proximal position if it hasn't already been movedthere by the surgeon.

To couple another surgical instrument assembly 20 to manipulatorassembly 4, the assistant(s) A grabs another assembly 20 from table T,laterally urges wrist unit shaft 56 into opening 80 of wrist unitadaptor 52, and then moves wrist unit 22 downward so that surgical tool62 resides within cannula 66 (see FIGS. 1 and 3B). This downwardmovement of wrist unit 22 automatically mates the electrical couplingsand motion feed-throughs (not shown) within wrist cap 58 and wrist unitadaptor 52. The system may include a control mechanism configured tolock carriage 122 travel at the top or proximal position, e.g., byactuating a brake (not shown), until the couplings are mated and wristunit 22 is no longer being moved downward. At this point, the surgeon Smay continue the surgical procedure.

The system and method of the present invention preferably includes amechanism for counting the number of times wrist unit 22 is decoupledand coupled from wrist unit adaptor 52. In this manner, the manufacturermay limit the number of times wrist unit 22 can be used. In a specificconfiguration, an integrated circuit chip (not shown) is housed withinwrist cap 58. The circuit chip counts the number of times wrist unit 22is coupled to wrist unit adaptor 52, e.g., 20 times, and a warning showsup on the surgeon's console C. The control system then downgrades theperformance of the system by reducing the load it can deliver orincreasing apparent backlash.

1-13. (canceled)
 14. A robotic surgical assembly for transferring motionfrom a drive component to a surgical tool, the assembly comprising: a) ahousing coupled to the drive component; b) an adaptor for receiving awrist unit comprising a wrist pivotally coupled to the surgical tool; c)a carriage coupled with the housing and with the adaptor, the carriageadapted to transfer motion from the drive component through a pluralityof motion feedthroughs to the adaptor; and d) a sterile drape betweenthe carriage and the adaptor, the drape having at least one hole toallow the carriage to be coupled with the adaptor; wherein the adaptoris configured to transfer motion from the plurality of motionfeedthroughs to the wrist unit to move the surgical tool in yaw andpitch about the wrist.
 15. The robotic surgical assembly of claim 14,the housing having a longitudinal Z-axis, the carriage configured tomove along the Z-axis of the housing.
 16. The robotic surgical assemblyof claim 15, the housing further comprising at least one carriage cabledrive coupled to at least one rotatable pulley, wherein the at least onecarriage cable drive is configured to move the carriage along the Z-axisof the housing.
 17. The robotic surgical assembly of claim 14, the drivecomponent comprising a manipulator assembly including a manipulator armhaving proximal and distal end portions.
 18. The robotic surgicalassembly of claim 14, the adaptor further comprising at least oneelectrical connector for transferring an electrical signal from thedrive component to the surgical tool.
 19. The robotic surgical assemblyof claim 14, the adaptor further comprising at least one electricalconnector for transferring an electrical signal from the surgical toolto the drive component.
 20. The robotic surgical assembly of claim 19,the electrical signal transferred from the surgical tool to the drivecomponent comprising indicating a number of times the surgical tool hasbeen used.
 21. The robotic surgical assembly of claim 20, the electricalsignal indicating a number of times the tool has been coupled to thesurgical assembly.
 22. The robotic surgical assembly of claim 14,further comprising a master manipulator for accepting commands from anoperator, the surgical tool moved in response to the commands acceptedby said master manipulator from the operator.
 23. The robotic surgicalassembly of claim 14, the surgical tool comprising an endoscope.